public class Example4_5 {
   public static void main(String args[]) {
      Rect ractangle = new Rect();
      ractangle.width = 109.87;
      ractangle.height = 25.18;
      double area=ractangle.getArea();
      System.out.println("矩形的面积:"+area);
      Lader lader = new Lader();
      lader.above = 10.798;
      lader.bottom = 156.65;
      lader.height = 18.12;
      area = lader.getArea();
      System.out.println("梯形的面积:"+area);
     }
}
